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.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Modified 1995-07-22 by Michael Chastain <mec@duracef.shout.net>:
.\" 'gethostname' is real system call on Linux/Alpha.
.\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2000-06-04, 2001-12-15 by aeb
.\" Modified 2004-06-17 by mtk
.\"
.TH GETHOSTNAME 2 2004-06-17 "Linux 2.6.7" "Linux Programmer's Manual"
.SH NAME
gethostname, sethostname \- get/set host name
.SH SYNOPSIS
.B #include <unistd.h>
.sp
.BI "int gethostname(char *" name ", size_t " len );
.br
.BI "int sethostname(const char *" name ", size_t " len );
.SH DESCRIPTION
These functions are used to access or to change the host name of the
current processor.
The
.B gethostname()
function returns a NUL-terminated hostname (set earlier by
.BR sethostname() )
in the array \fIname\fP that has a length of \fIlen\fP bytes.
In case the NUL-terminated hostname does not fit, no error is
returned, but the hostname is truncated. It is unspecified
whether the truncated hostname will be NUL-terminated.
.SH "RETURN VALUE"
On success, zero is returned. On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EFAULT
.I name
is an invalid address.
.TP
.B EINVAL
.I len
is negative or, for
.BR sethostname ,
.I len
is larger than the maximum allowed size,
or, for
.BR gethostname
on Linux/i386,
.I len
is smaller than the actual size.
(In this last case glibc 2.1 uses ENAMETOOLONG.)
.TP
.B EPERM
For
.BR sethostname ,
the caller did not have the
.B CAP_SYS_ADMIN
capability.
.SH "CONFORMING TO"
SVr4, 4.4BSD (this function first appeared in 4.2BSD).
POSIX 1003.1-2001 specifies
.B gethostname
but not
.BR sethostname .
.SH BUGS
For many Linux kernel / libc combinations
.B gethostname
will return an error instead of returning a truncated hostname.
.SH NOTES
SUSv2 guarantees that `Host names are limited to 255 bytes'.
POSIX 1003.1-2001 guarantees that `Host names (not including
the terminating NUL) are limited to HOST_NAME_MAX bytes'.
.SH "SEE ALSO"
.BR getdomainname (2),
.BR setdomainname (2),
.BR uname (2)
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